package main

import "fmt"
import "strings"
import "jvmgo/ch03/classfile"
import "jvmgo/ch03/classpath"

func main() {
    cmd := parseCmd()

    if cmd.versionFlag {
        fmt.Println("version 0.0.1")
    } else if cmd.helpFlag || cmd.class == "" {
        printUsage()
    } else {
        startJVM(cmd)
    }
}

func startJVM(cmd *Cmd) {
    cp := classpath.Parse(cmd.XjreOption, cmd.cpOption)
    className := strings.Replace(cmd.class, ".", "/", -1)
    cf := loadClass(className, cp)
    fmt.Println(cmd.class)
    printClassInfo(cf)
}

func loadClass(className string, cp *classpath.Classpath) *classfile.ClassFile {
    classData, _, err := cp.ReadClass(className)
    if err != nil {
        panic(err)
    }

    cf, err := classfile.Parse(classData)
    if err != nil {
        panic(err)
    }

    return cf
}

func printClassInfo(cf *classfile.ClassFile) {
    fmt.Printf("version: %v.%v\n", cf.MajorVersion(), cf.MinorVersion())
    fmt.Printf("constants count: %v\n", len(cf.ConstantPool()))
    fmt.Printf("access flags: 0x%x\n", cf.AccessFlags())
    fmt.Printf("this class: %v\n", cf.ClassName())
    fmt.Printf("super class: %v\n", cf.SuperClassName())
    fmt.Printf("interfaces: %v\n", cf.InterfaceNames())
    fmt.Printf("fields count: %v\n", len(cf.Fields()))
    for _, f := range cf.Fields() {
        fmt.Printf("  %s\n", f.Name())
    }
    fmt.Printf("methods count: %v\n", len(cf.Methods()))
    for _, m := range cf.Methods() {
        fmt.Printf("  %s\n", m.Name())
    }
}